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Glossary of Research Terms

This glossary is designed to help you, the consumer, become familiar with common terms used in clinical trials.

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ADVERSE EVENT: Any change in health that occurs in a person after he or she enrolls in a clinical trial. Not every adverse event is related to the treatment or test being studied, but researchers must report all adverse events to the Food and Drug Administration (FDA). 

ADVERSE REACTION: An unwanted effect caused by the administration of drugs. Onset may be sudden or develop over time. 

APPROVED DRUGS: In the United States, the Food and Drug Administration (FDA) approves prescription drugs. Before a doctor can prescribe a drug, it must undergo extensive testing and be approved by the FDA. The approval process for the FDA requires that a drug be tested in animals or medical labs (pre-clinical) before it is tested in humans. If the FDA finds the drug to be safe in the pre-clinical testing, then the drug is approved for the next phase of study. The next phase involves humans. The drug manufacturer then files a New Drug Application to the FDA. The FDA reviews the application and the drug is either approved or rejected. 

ARM: A treatment or test group in a randomized clinical trial. Trials with more than one treatment are said to have multiple arms. 

BASELINE: A person's health status before he or she begins treatment in a clinical trial. Baseline measurements are used as a reference point to determine a participant's response to the experimental treatment. Safety and efficacy of a drug are often evaluated by monitoring changes from baseline values. 

BIAS: Partial judgment on issues relating to the subject of that point of view. Bias is controlled in clinical trials by blinding and randomization. 

BLIND OR BLINDED TRIAL: A trial in which the participant is not informed as to what arm (experimental or control) of the clinical trial he or she is on. 

CLINICAL TRIAL: A carefully planned study that evaluates the benefits and risks of treatments and screening tests on humans. Well-designed clinical trials are the fastest and safest way to find treatments that work in people. Clinical trials are also called research studies or medical research.

COMPASSIONATE USE: The use of experimental treatments and drugs that haven't been approved by the FDA for use in humans. This is typically done for very sick people who have no other treatment options, and this use often requires approval from the FDA on a case-by-case basis. 

CONTRAINDICATION: A specific situation that will cause the administration of a treatment to be harmful to a person. 

CONTROL GROUP: The control group is the measure to gauge the effectiveness of the experimental treatment. Generally, the control group receives the placebo or currently accepted treatment for that particular illness. 

DATA SAFETY AND MONITORING BOARD (DSMB): An independent committee, composed of community representatives and clinical research experts who review data while a clinical trial is in progress. The review is done to ensure that participants are not exposed to undue risk. A DSMB may recommend that a trial be stopped if there are safety concerns or if the trial objectives have been achieved. 

DIAGNOSTIC TRIALS: Trials that are conducted to find better tests or procedures for diagnosing a particular disease or condition. Diagnostic trials usually include people who have signs or symptoms of the disease or condition being studied. 

DOSE-LIMITING TOXICITY: An adverse event or reaction during treatment on a clinical trial that prevents the dose of the study drug from being increased or to prevent continuation of treatment at any dosage level. 

DOUBLE-BLIND TRIAL: A clinical trial where neither the participant nor the investigator know which treatment the participant is receiving. The goal of this type of study is to eliminate bias in reporting results. 

EFFICACY: The ability of a drug, test or treatment to relieve symptoms, detect or eliminate the disease. 

EPIDEMIOLOGY: The branch of medical science that deals with the study of incidence and distribution and control of a disease among a specific group. 

EXCLUSION CRITERIA: The standards as outlined in the protocol, used to determine whether a person may or may not be allowed to participate in a clinical trial. See also inclusion. 

EXPANDED ACCESS: Procedures set forth by the FDA, such as compassionate use, parallel track, and treatment IND that distribute experimental drugs to participants who are not responding to currently available treatments for their condition and who are also unable to participate in other ongoing clinical trials. 

EXPERIMENTAL DRUG: A drug that is not approved by the FDA for use in humans, or approved as a treatment for a particular indication. 

FOOD AND DRUG ADMINISTRATION (FDA): The U.S. Department of Health and Human Services agency that is responsible for ensuring the safety and effectiveness of all drugs, biologics, vaccines, and medical devices. 

GENERALIZABILITY OF RESULTS: The extent to which clinical trial results apply to individuals being treated outside the trial. The results and conclusions of a study of one group of people may not apply equally to another group. Researchers must take care not to generalize their results too broadly. Often more studies are conducted to see how the treatment works in different groups of people. 

HYPOTHESIS: A supposition or assumption used as a basis of reasoning and experimentation. 

INCLUSION CRITERIA: The standards as outlined in the protocol used to determine whether a person might be allowed to participate in a clinical trial. It is important to note that inclusion and exclusion criteria are not used to reject people personally, but rather to identify appropriate participants and keep them safe. 

INFORMED CONSENT: The process of learning the key facts, risks and benefits about a clinical trial in order to decide whether or not to participate. It is also a continuing process of education to the participant throughout the life of the trial. 

INFORMED CONSENT DOCUMENT: A document that contains certain elements as mandated by the Code of Federal Regulations. The informed consent document contains information regarding the trial, such as purpose, background, risks, benefits, procedures, costs, confidentiality, contacts and patient rights. The participant must sign this document before beginning the trial. The Institutional Review Board approves the document. 

INSTITUTIONAL REVIEW BOARD (IRB): A group that reviews studies proposed by investigators. Each institution that conducts research has an IRB made up of researchers and members of the public. The IRB must be sure that the study is managed in a way that protects those who participate in it. All clinical trials by federal regulation must be approved by the IRB prior to enrolling participants. 

INVESTIGATIONAL NEW DRUG (IND): A new drug that is used in a clinical investigation. 

NEW DRUG APPLICATION (NDA): An application submitted by the manufacturer of a drug to the FDA for a license to market the drug for a specific indication. The application is submitted after all phases of clinical trials have been completed. 

OFF-LABEL USE: A drug prescribed for conditions other than those approved by the FDA. 

OPEN-LABEL TRIAL: A clinical trial in which doctors and participants know which treatment is being administered. 

ORPHAN DRUGS: An FDA category that refers to medications used to treat rare diseases and conditions. There is little financial incentive for the pharmaceutical industry to develop medications for these diseases or conditions. Orphan drug status, however, gives a manufacturer specific financial incentive to develop and provide such medications. 

PEER REVIEW: Review of a clinical trial by experts. These experts review the trials for scientific merit, participant safety, and ethical considerations. 

PHARMACOKINETICS: The processes (in a living organism) of absorption, distribution, metabolism, and excretion of a drug or vaccine. 

PHASE I TRIALS: The first phase of a drug trial. Generally, Phase I studies use drugs that have never been used in humans before. The goal is to obtain the maximum tolerated dose and to gain early evidence of efficacy. A small number of participants are used in this phase. 

PHASE II TRIALS: The second phase of drug trials. Generally, larger groups of participants are used than that of Phase I trials. Phase II trials further evaluate efficacy and safety. 

PHASE III TRIALS: The third phase of drug trials. Large groups of participants are enrolled in this study phase. The goal is to confirm effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely. 

PHASE IV TRIALS: Post-marketing studies to delineate additional information including the drug's risks, benefits, and optimal use. 

PLACEBO: An inactive pill, liquid, or powder that has no treatment value. 

PLACEBO CONTROLLED STUDY: A method of investigating drugs that utilizes a placebo. The placebo is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition. 

PRECLINICAL: A laboratory or animal study that's done to determine if a new treatment is safe and effective enough to be studied in humans. 

PREVENTION TRIALS: A type of trial to find better ways to prevent disease in people who have never had the disease or to prevent a disease from returning. Approaches may include medicines, vitamins, vaccines, minerals, or lifestyle changes. 

PROTOCOL: The specific set(s) of goals and procedures that define what will happen in a clinical trial. Protocols are developed before a trial begins so that participants know what will happen and other researchers can follow the same protocol. A protocol describes eligibility; the schedule of tests, procedures, medications, and treatment dosages; and the length of the study. 

QUALITY OF LIFE TRIALS: Trials that explore ways to improve comfort and quality of life for individuals with a chronic illness. 

RANDOMIZATION: A process that reduces the likelihood of bias by assigning people to treatment groups by chance alone (randomly). When groups are created by random assignment, individual characteristics are less likely to make the results inaccurate or bias. 

RANDOMIZED TRIAL: A study where participants are randomly (by chance) assigned to one of two or more treatment arms of a clinical trial. Occasionally placebos are utilized. 

SIDE EFFECTS: Any negative effects of a drug or treatment. Experimental drugs and treatments must be evaluated for both immediate and long-term side effects such as headache, nausea, hair loss, skin irritation or other physical problems. See also adverse event and serious adverse event. 

SINGLE-BLIND STUDY: A study where one party, either the investigator or participant, is unaware of what medication the participant is taking. 

SPONSOR: The organization that develops the treatment, drug or test, designs the study, and pays for costs associated with the clinical trial. 

STANDARD TREATMENT: The treatment that is normally provided to people with a given condition. The standard treatment has FDA approval. In many studies, a control group receives the standard treatment while a treatment group receives the experimental treatment. After the trial, researchers compare the outcomes of the two groups to see if the experimental treatment is better than, as good as, or not as beneficial as the standard treatment. 

STUDY COORDINATOR: The person at a medical center or research facility who manages the daily activities of the study, including coordinating the treatment or testing of participants and reporting events of the study. 

STUDY ENDPOINT: A primary or secondary outcome used to judge the effectiveness of a treatment.

TOXICITY: Specific adverse events attributable to a drug or treatment.

TREATMENT GROUP: The group of participants who receive an experimental treatment.

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